My newest, B sized, miniature gelding came to me roached, and I'm keeping him that way. It is clear he has a HEAVY mane, and I just don't want to have to deal with it! He is (gasp!) unregistered, so breed shows are no issue, and honestly, were I to be able to enter a 'real' CDE(there are none within many miles, and I am not really free to travel), I would do it with him just as he is...roached, but with a forelock and witherlock--the way he came, and the way I was used to; when I was young, it was common for QHs, which is what I had then, to be roached, and I actually like it on many horses. Sure is simpler, too!
As for the mini breed registries, I'm not sure it is "illegal" to have a horse roached, but would concede that judges might have apoplexy if you presented one as such---and most would likely use that as a 'reason' not to use such a horse (although when you have a 'bridle path' that goes 2/3 of the way down a horse's neck, as I've (amazingly!)seen, you are darn near 'there', anyway, so ????) Admittedly, I have NOT perused either AMHA or AMHR's current Rulebooks(and am not going to take the time to do so here and now) as to whether this is SPECIFICALLY addressed, but I don't recall that it is...??)
Margo